Developmental processes are activated and shaped by stimulation. Sources of stimulation, or experience can be found within the developing organism;s habitat. We have identified and quantified biological stimuli that are normally present in the prenatal and natal habitats of the Norway rat. Maternal behavior and physiology provide tactile, vestibular and thermal stimulation to fetal and newborn mammals. Perinatal rats receive stimulation associated with maternal locomotion, rearing and self-grooming during gestation, uterine contractions during labor, and licking, carrying, and retrieving following delivery into the nest. Maternally-derived stimuli are perceived by fetal and newborn rats, as evidenced by our finding that simulations of biological sensory events evoke behavioral and autonomic responses in perinatal rats. We have also accrued evidence that these stimuli facilitate fetal and newborn respiratory behavior, and the first nipple attachment in rats, thereby making important contributions to the transition from prenatal to postnatal life. In the current application, we propose studies of sensory function, attention, and associative learning in feat and newborn rats. and investigate contributions of these mechanisms to the postpartum emergence of an integrative, adaptive behavior in rats, namely, the first nipple attachment. The initial studies test the hypothesis that cardiac and behavioral responses of fetal newborn rats are expression of the orienting reflex, an attentional mechanism. A second set of experiments addresses fundamental issues of whether biological stimuli support processes of habituation and associative learning in perinatal rats. A final set of experiments tests the hypothesis that prenatal stimulation derived from the mother produces behavioral activation in fetuses, which specifies sensory controls of the first nipple attachment. This series of investigations will lead to improved understanding of sensory- perceptual, attentional, and learning processes during fetal and neonatal life, and will support additional studies of early behavioral structure, organization, and control.